organic acids with ht 200 s
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8/19/2019 Organic acids with HT 200 S
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Organic acids with HT 200 S Application APP-PHM-0011
General
Organic acids are an important parameter when it comes to
evaluating biological processes in a digestion tower and in
activated sludge. Determination of organic acids also plays a
signicant role in fermenter monitoring at fermentation plants.
Firstly, organic acids are contained by degradative processes in the
sewage network and in preliminary sedimentation of activated
sludge, and they affect the level of denitrication and the
elimination of biological phosphates.
Secondly, if the fermentation process is sound, the values of the
low-molecular fatty acids are to be collectively recorded as an
acetic acid equivalent, and a concentration between 500 mg/l and
3000 mg/l is to be maintained. Larger concentrations can cause a
change in the pH value, which would lead to a serious malfunction
of the fermentation plant.
With LCK365, the concentration of organic acids can be easily
recorded and photometrically determined.
During the ten-minute heating up period (at 100° C), the organic
acids are esteried, stained and then photometrically determined.
Method
As per the LCK365 instructions, the LT 200 thermostat is
pre-heated to 100° C for esterication, and the cuvettes are heated
at 100° C for ten minutes.
The LCK365 can also be implemented with HACH LANGE
HT 200 S thermostats. The method can be manually stored, the
pre-heating process eliminated and the end of the reaction time
indicated by means of an audio signal.
Material
LCK365 Cuvette test for organic acids●
LTV077 HT 200 S High temperature thermostat●
HACH LANGE Photometer●
EN
Determining the content
Sample preparation
The samples to be examined must be free of particles and ltered
if necessary. The digested sludge must always be ltered or
centrifuged.
Work process
To program the HT 200 S for the organic acid test, the HT 200 S is
started rst of all, and then the following programming procedure is
performed:
òPRG Cuvette test of organic acids
òPRG NAME Use the left button to scroll through the
alphabet and the numerical sequence.
Use the 2nd button from the left to
insert an additional character.
(For example, OA for organic acids)
OK Conrm entry
òPRG TEMP [°C] Use the left button to scroll through the
temperatures in increments of 5° C up
to 100° C.
OK Conrm entry
òPRG TIME
[minutes]
Use the left button to scroll through the
reaction times in intervals of 5 minutes
up to 10 minutes.
OK Conrm entry
òPRG POSITION Use the left button to select the position
currently free where the program is to
be saved.
OK Conrm entry
òConrm programming
To select the newly programmed method, press the arrow , select
the programmed method name, and then conrm.
Program overview
Name: e.g. OA
Temperature: 100° C
Time: 10 minutes
At the end of the program, the audio signal will sound; the cuvettes
can now be taken out of the thermostat to cool down (warning:
hot! 50° C). After exposure, please shake the cuvettes by inverting.
The test results obtained from heating in the LT 200 can be
compared with the results obtained from heating in the HT 200 S.
Curve chart: standard measurements with DIN acid standard
solution after exposure in the LT 200 thermostat and HT 200 S high
temperature thermostat. Measurement in DR5000 at 497 nm.
LCK365 measurements with DIN 38414-S19 acid standard solution
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Measurements
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HT 200 S
LT 200
Linear (LT 200)
Linear (HT 200 S)